Cytopilin 250 (testosterone cypionate)

Nandrolone is proven to be a progestin. This fact is of clear importance in bodybuilding, because while moderate Deca-only use actually lowers estrogen levels as a consequence of reducing natural testosterone levels and thus allowing the aromatase enzyme less substrate to work with, Deca nonetheless can cause gyno in some individuals. Furthermore, just as progesterone will to a point increase sex drive in women, and then often decrease it as levels get too high, high levels of progestogenic steroids can kill sex drive in male bodybuilders, though there is a great deal of individual variability as to what is too much.
Incidentally, this progestogenic activity also inhibits LH production, and contrary to common belief, even small amounts of Deca are quite inhibitory, approximately as much so as the same amount of testosterone.

Testosterone bind to the androgen receptor, reduced to 5α-dihydrotestosterone (DHT) by enzyme 5-alpha reductase. DHT-receptor complex undergoes a structural change, bind directly to specific nucleotide sequences of the chromosomal DNA and influence transcriptional activity of certain genes, producing the androgen effects.
Testosterone Cypionate mode of action is to increase nitrogen retention in the muscle. It is also known to increase levels of growth factor IGF-1 in both muscle tissue and in the liver.In addition to this, testosterone increases the activity of ‘satellite cells’. These are cells which surround the muscle tissue and play an active role in repairing damaged muscle tissue and contribute to the growth of new muscle.